1. Gary MarsdenSlide 1University of Cape Town Usability - does it exist?  Before we can look at usability, we have to look at how it is currently perceived  To do this, we need to analyse how users know that a product is ‘usable’  This is not as easy as it sounds. A good place to start looking is by analysing the tasks products are designed to solve.

2. Gary MarsdenSlide 2University of Cape Town Task types - external  For some products, it is easy to see how well they fulfil their role: –chair, car, hi-fi, television  This type of product is designed to fulfil some need that exists in the physical world.  This type of task we shall call “external” and is not interesting to our discussion.

3. Gary MarsdenSlide 3University of Cape Town Task types - internal  The other type of task is an “internal” task.  Here a device is built to solve a problem which exists only because the device exists!  With these internal tasks, the problem is defined in terms of the device created to solve the problem – this makes assessing task performance incredibly difficult.

4. Gary MarsdenSlide 4University of Cape Town Visibility - Physical and DM  Another problem in assessing usability is the lack of visibility in electronic devices  Physical devices have visible qualities which we can assess  Software can be visible (Direct Manipulation) but also invisible (DOS)  Electronics have physical attributes which are not worth investigating

5. Gary MarsdenSlide 5University of Cape Town Direct Manipulation (Ben Shneiderman)  From studies on video games, decided that: –Users should see objects –Objects should be controlled directly –State is always visible  This led to interfaces such as the Star, Lisa and Macintosh

6. Gary MarsdenSlide 6University of Cape Town Visibility - gadget  Direct manipulation has helped with software, but most computers are sold in embedded systems  Cellular handsets etc. have limited interfaces  This was OK when processors were under powered, not acceptable now

7. Gary MarsdenSlide 7University of Cape Town Masochism  Before we go on to look at usable systems, it is worth mentioning that some people like unusable systems –Computer games rely on having obscure interfaces –The World Wide Web it is fun to just surf around hoping to bump into something interesting

8. Gary MarsdenSlide 8University of Cape Town Introducing usability to products  I hope I have convinced you in the first lecturer that devices are not as usable as they might be  One possible explanation for this is that the technology is not mature enough yet to allow usability it to develop

9. Gary MarsdenSlide 9University of Cape Town Mature technology  Let us switch briefly to an more mature technology as a case study: cars –Originally sold on the fact they worked –Later came technologies (“Balanced Power”) –Ultimately came safety and usability Ralph Nader changed perception of this

10. Gary MarsdenSlide 10University of Cape Town Electronic maturity  So is the electronic industry in a mature state?  To answer this we need to look at Christensen’s ideas (MIT professor looking at “disruptive” technology l t He assumes that technology develops over time and eventually reaches some level where it is sufficient for a task This is true for “external” tasks

11. Gary MarsdenSlide 11University of Cape Town Internal task maturity  This time, the graph looks a little different  The curve never meets the task line, as the line changes to keep ahead of the curve  What is going on? l

12. Gary MarsdenSlide 12University of Cape Town Capitalism  Companies exist to make money for their share holders. This means that they need to keep selling products to the same consumers  Unlike cars (or other physical products), software (and electronics) does not ware out  Therefore, companies must make you want to buy new products - the technology curve cannot be allowed to cross the task line.

13. Gary MarsdenSlide 13University of Cape Town Task stepping  There are many ways to produce a stepped task curve. Here are three: –Forwards compatibility Having software versions which are incompatible –Processor exploitation Here is a quote from a Microsoft executive: –“if we hadn’t brought your processor to its knees, why else would you get a new one.” –Snobbery Word processing - “font-itis”, “clipart-itis” etc.

14. Gary MarsdenSlide 14University of Cape Town Usability exploitation  Companies can also exploit usability to step the task line using marketing and drama –Drama Exploits the fact that products can be made to look easy to use at purchase time Sales people use “demo” buttons or careful walkthroughs –This is backed by marketing Microsoft head of marketing “perception is reality” Techno-centric focus (“Super-Intelligent control”)

15. Gary MarsdenSlide 15University of Cape Town Complicity  Most users are happy to be exploited in this way for many reasons  Don’t want to admit they have made a bad decision  Enjoy the kudos that comes from knowing a system and helping others Early adopters buy for fashion purposes  Moreover, users do not know that there are better ways of doing things as the technology is hard to understand, users assume un-usability is essential

16. Gary MarsdenSlide 16University of Cape Town Increasing usability awareness  Before we start to look at how programmers improve usability, it is worth considering how usability awareness can be raised –Commercial new user groups and applications, esp. cellular phones little need whilst still selling –Academic little impact in three decades –Consumer groups need to develop usability standards (I have done a lot of work here)